Many different devices and methods have been used for skin treatments intended to improve the texture and appearance of the skin. All share a common mechanism, i.e., they selectively destroy a portion of the skin allowing the body to heal with fresh, new, and hopefully undamaged skin cells. Recovery time from such procedures is in direct correlation to the depth of skin destruction.
Existing devices and methods also share another common feature, i.e., none of them provide a method of monitoring the depth of treatment while the destruction is actually occurring. Rather, the clinician must follow a protocol and visibly observe changes in the skin to yield treatment which is deep enough to be effective, but not too deep to cause scarring, pigmentation changes, or prolonged healing. The difficulty of achieving accuracy in treatment is compounded, for example, by changes in skin thickness and blood flow from one body area to another as well as patient to patient differences in skin type, pigmentation, degree of sun damage, and general health of the skin.
More specifically, cyrosurgery with liquid nitrogen has been used for decades to freeze off skin lesions, such as warts and other non-malignant growths. Application of the liquid nitrogen causes a coagulative necrosis of whatever viable tissue it contacts. The key advantage of cryosurgery over other ablative techniques is the fact that cold temperatures are much better tolerated by the patient than hot temperatures. A laser or thermal cautery would be equally effective for removal of skin lesions, but these methods are painful and poorly tolerated by the patient in the absence of an anesthetic. The disadvantages of cryosurgery, on the other hand, include a lack of precise control of the zone of tissue ablation and difficulty achieving limited zones of tissue ablation due to the extremely low temperature of liquid nitrogen relative to body temperature. It is also difficult to achieve any change in the tissue other than ablation due to the extremely low temperatures associated with liquid nitrogen. This essentially precludes any tissue treatment other than ablation.
Others have attempted to overcome the disadvantages associated with laser or thermal cautery devices by using cryogen spray to cool the treatment area during the procedure which results in a more tolerable, but temporary, anesthesia effect. Despite the improvement, none of these devices provide real-time monitoring of the skin while the cooling process is taking effect to ensure that the skin has been cooled sufficiently to provide the desired anesthetic effect. Even more, none of the noted devices are designed for convenient and simple operation by a user or for monitoring of the temperature near the treatment site by the user.
Accordingly, a need exists for a device and related method for effecting change in tissue at a treatment site which monitors the temperature at the treatment site in order to provide real time feedback during treatment. The device would also control the temperature of the tissue at the treatment site dependent upon the sensed temperature in order to effect changes other than simple ablation. The device would be easy to use and provide features designed to limit patient risk. The device could also be designed to be operated by the user with a single hand. Even more, the device could be designed to be positioned on one or more fingers of the user allowing adjacent fingers to stabilize the device during use and monitor the temperature of the skin surrounding the treatment area. All of these features are provided by the following invention. Naturally, any improvements along such lines should contemplate good engineering practices, such as simplicity, ease of implementation, unobtrusiveness, stability, etc.